Structural mechanisms for gating and ion selectivity of the human polyamine transporter ATP13A2.

Mutations in ATP13A2, also known as PARK9, cause a rare monogenic form of juvenile-onset Parkinson's disease named Kufor-Rakeb syndrome and other neurodegenerative diseases. ATP13A2 encodes a neuroprotective P5B P-type ATPase highly enriched in the brain that mediates selective import of spermine ions from lysosomes into the cytosol via an unknown mechanism. Here we present three structures of human ATP13A2 bound to an ATP analog or to spermine in the presence of phosphomimetics determined by cryoelectron microscopy. ATP13A2 autophosphorylation opens a lysosome luminal gate to reveal a narrow lumen access channel that holds a spermine ion in its entrance. ATP13A2's architecture suggests physical principles underlying selective polyamine transport and anticipates a "pump-channel" intermediate that could function as a counter-cation conduit to facilitate lysosome acidification. Our findings establish a firm foundation to understand ATP13A2 mutations associated with disease and bring us closer to realizing ATP13A2's potential in neuroprotective therapy.

An alphacoronavirus polymerase structure reveals conserved replication factor functions.

Coronaviruses are a diverse subfamily of viruses containing pathogens of humans and animals. This subfamily of viruses replicates their RNA genomes using a core polymerase complex composed of viral non-structural proteins: nsp7, nsp8 and nsp12. Most of our understanding of coronavirus molecular biology comes from betacoronaviruses like SARS-CoV and SARS-CoV-2, the latter of which is the causative agent of COVID-19. In contrast, members of the alphacoronavirus genus are relatively understudied despite their importance in human and animal health. Here we have used cryo-electron microscopy to determine structures of the alphacoronavirus porcine epidemic diarrhea virus (PEDV) core polymerase complex bound to RNA. One structure shows an unexpected nsp8 stoichiometry despite remaining bound to RNA. Biochemical analysis shows that the N-terminal extension of one nsp8 is not required for in vitro RNA synthesis for alpha- and betacoronaviruses. Our work demonstrates the importance of studying diverse coronaviruses in revealing aspects of coronavirus replication and identifying areas of conservation to be targeted by antiviral drugs.

Quantitative interaction proteomics and genome-wide profiling of epigenetic histone marks and their readers.

Trimethyl-lysine (me3) modifications on histones are the most stable epigenetic marks and they control chromatin-mediated regulation of gene expression. Here, we determine proteins that bind these marks by high-accuracy, quantitative mass spectrometry. These chromatin "readers" are assigned to complexes by interaction proteomics of full-length BAC-GFP-tagged proteins. ChIP-Seq profiling identifies their genomic binding sites, revealing functional properties. Among the main findings, the human SAGA complex binds to H3K4me3 via a double Tudor-domain in the C terminus of Sgf29, and the PWWP domain is identified as a putative H3K36me3 binding motif. The ORC complex, including LRWD1, binds to the three most prominent transcriptional repressive lysine methylation sites. Our data reveal a highly adapted interplay between chromatin marks and their associated protein complexes. Reading specific trimethyl-lysine sites by specialized complexes appears to be a widespread mechanism to mediate gene expression.

Boosting the Sensitivity of Quantitative Single-Cell Proteomics with Infrared-Tandem Mass Tags.

Single-cell proteomics is a powerful approach to precisely profile protein landscapes within individual cells toward a comprehensive understanding of proteomic functions and tissue and cellular states. The inherent challenges associated with limited starting material demand heightened analytical sensitivity. Just as advances in sample preparation maximize the amount of material that makes it from the cell to the mass spectrometer, we strive to maximize the number of ions that make it from ion source to the detector. In isobaric tagging experiments, limited reporter ion generation limits quantitative accuracy and precision. The combination of infrared photoactivation and ion parking circumvents the m/z dependence inherent in HCD, maximizing reporter generation and avoiding unintended degradation of TMT reporter molecules in infrared-tandem mass tags (IR-TMT). The method was applied to single-cell human proteomes using 18-plex TMTpro, resulting in 4-5-fold increases in reporter signal compared to conventional SPS-MS3 approaches. IR-TMT enables faster duty cycles, higher throughput, and increased peptide identification and quantification. Comparative experiments showcase 4-5-fold lower injection times for IR-TMT, providing superior sensitivity without compromising accuracy. In all, IR-TMT enhances the dynamic range of proteomic experiments and is compatible with gas-phase fractionation and real-time searching, promising increased gains in the study of cellular heterogeneity.

Dynamic Assessment of Drain Fluid Amylase Estimates the Risk of CR-POPF Following Pancreatoduodenectomy.

OBJECTIVE: To evaluate whether drain fluid amylase levels on day-1 (DFA1) and day-3 (DFA3) can reliably estimate the risk of clinically relevant-postoperative pancreatic fistula (CR-POPF) following pancreatoduodenectomy (PD) compared to either value alone or in combination with clinicopathologic variables. BACKGROUND: CR-POPF is a major source of morbidity and mortality following PD. Current drain management algorithms are variable and are mostly dependent on DFA1, while the DFA3 is seldom utilized to guide clinical decision making. METHODS: Between 2015-2020, patients who underwent PD at two high-volume pancreas centers and had intraoperative drain placement with measurement of DFA1 and DFA3 were retrospectively reviewed. Models to predict CR-POPF were constructed using DFA1, DFA3, fistula risk score (FRS) and other patient or treatment-related parameters. The fittest and more parsimonious model was used to construct a CR-POPF risk calculator. RESULTS: Nine-hundred-twenty-three patients were included in the analysis. The FRS was high in 100(10.9%), intermediate in 524(57.3%), low in 211(23.1%) and negligible in 79(8.6%) patients. The overall rate of CR-POPF was 9.2%. Five logistic regression models were constructed using variables known to be implicated in CR-POPF. A model based solely on DFA1 and DFA3 with a cross-validated area under the curve of 0.846 was selected. A calculator using DFA1 and DFA3 was created based on this model to estimate the risk of CR-POPF. CONCLUSIONS: Risk of CR-POPF following pancreatoduodenectomy can be accurately estimated based on measurement of DFA1 and DFA3. Our CR-POPF kinetics calculator can facilitate postoperative risk stratification and guide drain management algorithms.

MSKI-RADS: An MRI-based Musculoskeletal Infection Reporting and Data System for the Diagnosis of Extremity Infections.

Background Current terms used to describe the MRI findings for musculoskeletal infections are nonspecific and inconsistent. Purpose To develop and validate an MRI-based musculoskeletal infection classification and scoring system. Materials and Methods In this retrospective cross-sectional internal validation study, a Musculoskeletal Infection Reporting and Data System (MSKI-RADS) was designed. Adult patients with radiographs and MRI scans of suspected extremity infections with a known reference standard obtained between June 2015 and May 2019 were included. The scoring categories were as follows: 0, incomplete imaging; I, negative for infection; II, superficial soft-tissue infection; III, deeper soft-tissue infection; IV, possible osteomyelitis (OM); V, highly suggestive of OM and/or septic arthritis; VI, known OM; and NOS (not otherwise specified), nonspecific bone lesions. Interreader agreement for 20 radiologists from 13 institutions (intraclass correlation coefficient [ICC]) and true-positive rates of MSKI-RADS were calculated and the accuracy of final diagnoses rendered by the readers was compared using generalized estimating equations for clustered data. Results Among paired radiographs and MRI scans from 208 patients (133 male, 75 female; mean age, 55 years ± 13 [SD]), 20 were category I; 34, II; 35, III; 30, IV; 35, V; 18, VI; and 36, NOS. Moderate interreader agreement was observed among the 20 readers (ICC, 0.70; 95% CI: 0.66, 0.75). There was no evidence of correlation between reader experience and overall accuracy (P = .94). The highest true-positive rate was for MSKI-RADS I and NOS at 88.7% (95% CI: 84.6, 91.7). The true-positive rate was 73% (95% CI: 63, 80) for MSKI-RADS V. Overall reader accuracy using MSKI-RADS across all patients was 65% ± 5, higher than final reader diagnoses at 55% ± 7 (P < .001). Conclusion MSKI-RADS is a valid system for standardized terminology and recommended management of imaging findings of peripheral extremity infections across various musculoskeletal-fellowship-trained reader experience levels. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Schweitzer in this issue.

Cluster randomized trial designs for modeling time-varying intervention effects.

Stepped-wedge cluster randomized trials (SW-CRTs) are typically analyzed assuming a constant intervention effect. In practice, the intervention effect may vary as a function of exposure time, leading to biased results. The estimation of time-on-intervention (TOI) effects specifies separate discrete intervention effects for each elapsed period of exposure time since the intervention was first introduced. It has been demonstrated to produce results with minimum bias and nominal coverage probabilities in the analysis of SW-CRTs. Due to the design's staggered crossover, TOI effect variances are heteroskedastic in a SW-CRT. Accordingly, we hypothesize that alternative CRT designs will be more efficient at modeling certain TOI effects. We derive and compare the variance estimators of TOI effects between a SW-CRT, parallel CRT (P-CRT), parallel CRT with baseline (PB-CRT), and novel parallel CRT with baseline and an all-exposed period (PBAE-CRT). We also prove that the time-averaged TOI effect variance and point estimators are identical to that of the constant intervention effect in both P-CRTs and PB-CRTs. We then use data collected from a hospital disinvestment study to simulate and compare the differences in TOI effect estimates between the different CRT designs. Our results reveal that the SW-CRT has the most efficient estimator for the early TOI effect, whereas the PB-CRT typically has the most efficient estimator for the long-term and time-averaged TOI effects. Overall, the PB-CRT with TOI effects can be a more appropriate choice of CRT design for modeling intervention effects that vary by exposure time.

Estimation and reduction of bias in self-controlled case series with non-rare event dependent outcomes and heterogeneous populations.

The self-controlled case series (SCCS) is a commonly adopted study design in the assessment of vaccine and drug safety. Recurrent event data collected from SCCS studies are typically analyzed using the conditional Poisson model which assumes event times are independent within-cases. This assumption is violated in the presence of event dependence, where the occurrence of an event influences the probability and timing of subsequent events. When event dependence is suspected in an SCCS study, the standard recommendation is to include only the first event from each case in the analysis. However, first event analysis can still yield biased estimates of the exposure relative incidence if the outcome event is not rare. We first demonstrate that the bias in first event analysis can be even higher than previously assumed when subpopulations with different baseline incidence rates are present and describe an improved method for estimating this bias. Subsequently, we propose a novel partitioned analysis method and demonstrate how it can reduce this bias. We provide a recommendation to guide the number of partitions to use with the partitioned analysis, illustrate this recommendation with an example SCCS study of the association between beta-blockers and acute myocardial infarction, and compare the partitioned analysis against other SCCS analysis methods by simulation.

The effect of deprescribing interventions on mortality and health outcomes in older people: An updated systematic review and meta-analysis.

AIMS: Previous systematic reviews suggest that deprescribing may improve survival, particularly in frail older people. Evidence is rapidly accumulating, suggesting a need for an updated review of the literature. METHODS: We updated a 2016 systematic review and meta-analysis to include studies published from inception to 26 April 2024 from specified databases. Studies in which older people had at least one medication deprescribed were included and grouped by study designs and targeted medications. The risk of bias was assessed using the Cochrane tool and the Newcastle-Ottawa tool. Odds ratios (OR) or mean differences were calculated as the effect measures using either the Mantel-Haenszel or generic inverse-variance method with fixed- or random-effects meta-analyses. The primary outcome was mortality. Secondary outcomes were adverse drug withdrawal events, physical health, cognitive function, quality of life and effect on medication regimen. Subgroup analyses were performed based on age and intervention types. RESULTS: A total of 259 studies (reported in 286 papers) were included in this updated review. Deprescribing polypharmacy did not result in a significant reduction in mortality in both randomized (OR 0.96, 95% confidence interval [CI] 0.84-1.09) and non-randomized studies (OR 0.70, 95% CI 0.36-1.38). Further subgroup analyses of randomized studies on deprescribing polypharmacy demonstrated a significant reduction in mortality in the young old (aged 65-79) (OR 0.71, 95% CI 0.51-0.99) and when patient-specific interventions were applied (OR 0.79, 95% CI 0.63-0.99). CONCLUSIONS: Deprescribing can be achieved with potentially important benefits in terms of improved survival, particularly when patient-specific interventions are applied and initiated early in the young old.

Impact of Neoadjuvant Therapy on Oncological Outcomes of Patients With Distal Pancreatic Adenocarcinoma.

BACKGROUND: Distal pancreatic ductal adenocarcinoma (D-PDAC) often presents at an advanced stage. The efficacy of neoadjuvant therapy (NAT) in improving outcomes for D-PDAC is not well-established. This study evaluates the impact of NAT on the oncological outcomes of patients with D-PDAC. METHODS: A retrospective cohort study of consecutive patients with resectable and borderline-resectable D-PDAC treated at a single center from 2012 to 2020 was performed. Stratification was based on initial treatment-NAT or surgery first (SF). Survival analysis, following intention-to-treat framework, used Kaplan-Meier and Cox regression to assess NAT's impact on progression-free survival (PFS) and overall survival (OS) of D-PDAC. RESULTS: Among 141 patients (median age 69.8 years, 51.8% females) included in the study, 71 (50.4%) received NAT and 70 (49.6%) were planned for SF. Patients receiving NAT were younger (65.9 vs. 72.6 years) and had higher incidence of borderline-resectable disease (31% vs. 4.3%) (both p < 0.05) than those undergoing SF. Thirteen patients (18.3%) undergoing NAT and five (7.1%) in SF group, failed to undergo resection. Univariate comparison showed no difference in the PFS (SF:13.97 vs. NAT:17.00 months, p = 0.6), and OS (SF:23.73 vs. NAT:32.53 months, p = 0.35). Multivariate Cox regression analysis noted significantly improved PFS (HR = 0.64, 95%CI = 0.42-0.96, p = 0.031) and OS (HR = 0.60, 95%CI = 0.39-0.93, p = 0.021) with NAT. CONCLUSION: NAT is associated with improved PFS and OS in patients with -D-PDAC. Further randomized controlled trials are warranted to confirm these findings.

Postoperative infectious complications worsen oncologic outcomes following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreaticoduodenectomy (PD) remains the only curative option for patients with pancreatic adenocarcinoma (PDAC). Infectious complications (IC) can negatively impact patient outcomes and delay adjuvant therapy in most patients. This study aims to determine IC effect on overall survival (OS) following PD for PDAC. STUDY DESIGN: Patients who underwent PD for PDAC between 2010 and 2020 were identified from a single institutional database. Patients were categorized into two groups based on whether they experienced IC or not. The relationship between postoperative IC and OS was investigated using Kaplan-Meier and Cox-regression multivariate analysis. RESULTS: Among 655 patients who underwent PD for PDAC, 197 (30%) experienced a postoperative IC. Superficial wound infection was the most common type of infectious complication (n = 125, 63.4%). Patients with IC had significantly more minor complications (Clavien-Dindo [CD] < 3; [59.4% vs. 40.2%, p < 0.001]), major complications (CD ≥ 3; [37.6% vs. 18.8%, p < 0.001]), prolonged LOS (47.2% vs 20.3%, p < 0.001), biochemical leak (6.1% vs. 2.8%, p = 0.046), postoperative bleeding (4.1% vs. 1.3%, p = 0.026) and reoperation (9.6% vs. 2.2%, p < 0.001). Time to adjuvant chemotherapy was delayed in patients with IC versus those without (10 vs. 8 weeks, p < 0.001). Median OS for patients who experienced no complication, noninfectious complication, and infectious complication was 33.3 months, 29.06 months, and 27.58 months respectively (p = 0.023). On multivariate analysis, postoperative IC were an independent predictor of worse OS (HR 1.32, p = 0.049). CONCLUSIONS: IC following PD for PDAC independently predict worse oncologic outcomes. Thus, efforts to prevent and manage IC should be a priority in the care of patients undergoing PD for PDAC.

Inclusion of unexposed clusters improves the precision of fixed effects analysis of stepped-wedge cluster randomized trials with binary and count outcomes.

BACKGROUND: The fixed effects model is a useful alternative to the mixed effects model for analyzing stepped-wedge cluster randomized trials (SW-CRTs). It controls for all time-invariant cluster-level confounders and has proper control of type I error when the number of clusters is small. While all clusters in a SW-CRT are typically designed to crossover from the control to receive the intervention, some trials can end with unexposed clusters (clusters that never receive the intervention), such as when a trial is terminated early due to safety concerns. It was previously unclear whether unexposed clusters would contribute to the estimation of the intervention effect in a fixed effects analysis. However, recent work has demonstrated that including an unexposed cluster can improve the precision of the intervention effect estimator in a fixed effects analysis of SW-CRTs with continuous outcomes. Still, SW-CRTs are commonly designed with binary outcomes and it is unknown if those previous results extend to SW-CRTs with non-continuous outcomes. METHODS: In this article, we mathematically prove that the inclusion of unexposed clusters improves the precision of the fixed effects intervention effect estimator for SW-CRTs with binary and count outcomes. We then explore the benefits of including an unexposed cluster in simulated datasets with binary or count outcomes and a real palliative care data example with binary outcomes. RESULTS: The simulations show that including unexposed clusters leads to tangible improvements in the precision, power, and root mean square error of the intervention effect estimator. The inclusion of the unexposed cluster in the SW-CRT of a novel palliative care intervention with binary outcomes yielded smaller standard errors and narrower 95% Wald Confidence Intervals. CONCLUSIONS: In this article, we demonstrate that the inclusion of unexposed clusters in the fixed effects analysis can lead to the improvements in precision, power, and RMSE of the fixed effects intervention effect estimator for SW-CRTs with binary or count outcomes.

Imaging of Peripheral Nerves: AJR Expert Panel Narrative Review.

Peripheral nerve imaging provides information that can be critical to the diagnosis, staging, and management of peripheral neuropathies. MRI and ultrasound are the imaging modalities of choice for clinical evaluation of the peripheral nerves given their high soft tissue contrast and high resolution, respectively. This AJR Expert Panel Narrative Review describes MRI- and ultrasound-based techniques for peripheral nerve imaging; highlights considerations for imaging in the settings of trauma, entrapment syndromes, diffuse inflammatory neuropathies, and tumor; and discusses image-guided nerve interventions, focusing on nerve blocks and ablation.

Trajectory of health-related quality of life during and after hospitalisation due to worsening of heart failure.

PURPOSE: This study aimed to examine the trajectory in health-related quality of life (HRQoL) during and after hospitalisation for worsening of heart failure (HF) in Malaysia. METHODS: 200 patients with heart failure and reduced ejection fraction (HFrEF) admitted into two hospitals in Malaysia due to worsening of HF were surveyed using the EQ-5D-5 L questionnaire. The primary outcomes were utility values at admission, discharge and 1-month post-discharge (1MPD). Secondary outcomes included the visual analogue scores (VAS) and the proportion of patients reporting each EQ-5D-5 L dimension levels. Missing data were imputed using multiple imputation, and generalised linear mixed models were fitted. RESULTS: At admission, the unadjusted mean utility values and VAS scores for HFrEF patients in Malaysia were as low as 0.150 ± 0.393 and 38.2 ± 20.8, respectively. After a median hospital stay of 4 days, there was a significant improvement in utility values and VAS scores by 0.510 (95% CI: 0.455-0.564) and 28.8 (95% CI: 25.5-32.1), respectively. The utility value and VAS score at 1-month post-discharge were not significantly different from discharge. The proportion of HFrEF patients reporting problems and severe problems in mobility, self-care, usual activities, and anxiety/depression, pain/discomfort reduced at varying degree from admission to discharge and 1MPD. CONCLUSION: HF is a progressive condition with substantial variation in HRQoL during the disease trajectory. During hospitalisation due to worsening of HF, HFrEF population has unfavourable HRQoL. Rapid and significant HRQoL improvement was observed at discharge, which sustained over one month. The study findings can inform future cost-effectiveness analyses and policies.

Heart failure is a progressive disease. Health-related quality of life of heart failure patients dynamically changes over time. Upon worsening of symptoms requiring hospital admission, the average level of health-related quality of life among people living with heart failure was low, approximately one-third of their perfect health. From the perspective of general public, this is equivalent to a health state that is near to being dead. Majority of patients had problems in mobility, self-care, usual activities, anxiety/depression and pain/discomfort. After receiving treatments in hospitals, most patients reported less problem in mobility, are able to take care of themselves and perform usual activities, feeling less pain/discomfort, and feeling less anxious/depressed. At discharge, their health state improved significantly by a large amount (equivalent to gaining half a year in perfect health), and this gain was sustained at 1-month post-discharge. This study provides policy makers insights on heart failure patients' disease experiences and quantifies their health-related quality of life during and after hospital admissions based on patients' disease experiences and general public's preference. In this way, both patients and public were involved in the policy-making process.

Prevalence and Impact of Workplace Sexual Harassment Experienced by Medical Sonographers.

OBJECTIVE: To assess the prevalence and impact of sexual harassment among a nationwide sample of medical sonographers. METHODS: A survey was distributed anonymously to a convenience sample of medical sonographers via email contacts and sonographer-specific social media pages. Data were analyzed to determine respondent demographics, the prevalence of sexual harassment in the last 2 years, the type and severity of harassment experienced, demographics of perpetrators, personal and institutional responses to such experiences, and the impact of sexual harassment on sonographer physical and mental health and job satisfaction. RESULTS: Of the 220 sonographers (83% female) most (45%) were between 18 and 34 years and identified as white (81%). A total of 192 (87%) reported experiencing at least 1 incident of harassment within the last 2 years. Female respondents experienced higher harassment rates (76%) compared to males (50%, P = .02). The most common forms of harassment were verbal, including suggestive or sexist jokes (69%) and offensive sexist remarks (61%). Perpetrators were predominantly male (78%) and most commonly patients (89%) or their friends/family members (46%). The majority of respondents either ignored the harassing behavior (70%) or treated it like a joke (50%), with only a minority (12%) officially reporting incidents. Of those who reported, 44% were unsatisfied with their institution's response. Among respondents, 34% reported negative impacts of workplace sexual harassment, such as anxiety, depression, sleep loss, or adverse workplace consequences. DISCUSSION: Workplace sexual harassment is a common occurrence for sonographers and often leads to negative health and career outcomes. Further institutional policies to prevent harassment and mitigate its effects are needed.

An open repository of real-time COVID-19 indicators.

The COVID-19 pandemic presented enormous data challenges in the United States. Policy makers, epidemiological modelers, and health researchers all require up-to-date data on the pandemic and relevant public behavior, ideally at fine spatial and temporal resolution. The COVIDcast API is our attempt to fill this need: Operational since April 2020, it provides open access to both traditional public health surveillance signals (cases, deaths, and hospitalizations) and many auxiliary indicators of COVID-19 activity, such as signals extracted from deidentified medical claims data, massive online surveys, cell phone mobility data, and internet search trends. These are available at a fine geographic resolution (mostly at the county level) and are updated daily. The COVIDcast API also tracks all revisions to historical data, allowing modelers to account for the frequent revisions and backfill that are common for many public health data sources. All of the data are available in a common format through the API and accompanying R and Python software packages. This paper describes the data sources and signals, and provides examples demonstrating that the auxiliary signals in the COVIDcast API present information relevant to tracking COVID activity, augmenting traditional public health reporting and empowering research and decision-making.

Diffusion tensor imaging of hamstring muscles after acute strain injury and throughout recovery in collegiate athletes.

OBJECTIVE: To identify the region of interest (ROI) to represent injury and observe between-limb diffusion tensor imaging (DTI) microstructural differences in muscle following hamstring strain injury. MATERIALS AND METHODS: Participants who sustained a hamstring strain injury prospectively underwent 3T-MRI of bilateral thighs using T1, T2, and diffusion-weighted imaging at time of injury (TOI), return to sport (RTS), and 12 weeks after RTS (12wks). ROIs were using the hyperintense region on a T2-weighted sequence: edema, focused edema, and primary muscle injured excluding edema (no edema). Linear mixed-effects models were used to compare diffusion parameters between ROIs and timepoints and limbs and timepoints. RESULTS: Twenty-four participants (29 injuries) were included. A significant ROI-by-timepoint interaction was detected for all diffusivity measures. The edema and focused edema ROIs demonstrated increased diffusion at TOI compared to RTS for all diffusivity measures (p-values < 0.006), except λ1 (p-values = 0.058-0.12), and compared to 12wks (p-values < 0.02). In the no edema ROI, differences in diffusivity measures were not observed (p-values > 0.82). At TOI, no edema ROI diffusivity measures were lower than the edema ROI (p-values < 0.001) but not at RTS or 12wks (p-values > 0.69). A significant limb-by-timepoint interaction was detected for all diffusivity measures with increased diffusion in the involved limb at TOI (p-values < 0.001) but not at RTS or 12wks (p-values > 0.42). Significant differences in fractional anisotropy over time or between limbs were not detected. CONCLUSION: Hyperintensity on T2-weighted imaging used to define the injured region holds promise in describing muscle microstructure following hamstring strain injury by demonstrating between-limb differences at TOI but not at follow-up timepoints.

"The Cost in the Individual": Longitudinal Burnout Prevalence Among Pediatric Emergency Physicians Through 9 Months of the COVID-19 Pandemic.

OBJECTIVES: Emergency medicine (EM) confers a high risk of burnout that may be exacerbated by the COVID-19 pandemic. We aimed to determine the longitudinal prevalence of burnout in pediatric EM (PEM) physicians/fellows working in tertiary PEM departments across Canada and its fluctuation during the pandemic. METHODS: A national mixed-methods survey using a validated 2-question proxy for burnout was distributed monthly through 9 months. The primary outcome was the trajectory in probability of burnout, which was examined as both emotional exhaustion (EE) and depersonalization (DP), EE alone, and DP alone. Secondary outcomes investigated burnout and its association with demographic variables. Quantitative data were analyzed using logistic regression for primary outcomes and subanalyses for secondary outcomes. Conventional content analysis was used to analyze qualitative data and generate themes. RESULTS: From February to October 2021, 92 of 98 respondents completed at least 1 survey, 78% completed at least 3 consecutive surveys, and 48% completed at least 6 consecutive surveys. Predicted probability of EE was bimodal with peaks in May (25%) and October (22%) 2021. Rates of DP alone or having both EE and DP were approximately 1% and stable over the study period. Mid-career physicians were at lower risk of EE (odds ratio, 0.02; 95% confidence interval, 0-0.22) compared with early-career physicians. Underlying drivers of burnout were multifaceted. CONCLUSIONS: Our study suggests that increased COVID-19 case burden was correlated with EE levels during the third and fourth waves of the pandemic. Emotional exhaustion was worsened by systemic factors, and interventions must target common themes of unsustainable workloads and overwhelming lack of control.

Managing deepsea oil spills through a systematic modeling approach.

Offshore oil exploration and production in deepwater are associated with environmental risks to marine ecosystems. This research introduces DWOSM (Deep Water Oil Spill Model), a three-dimensional Lagrangian model, which is developed to simulate the transport and fate of oil spills resulting from subsea blowouts. DWOSM comprises three interconnected modules: DWOSM-DSD, which predicts the oil droplet size distribution from a blowout release; DWOSM-NearField, simulating plume dynamics and tracking oil droplets within the plume region; and DWOSM-FarField, modeling the evolution of dispersed oil beyond the near-field. Compared to other oil spill models, this integrated approach improves the transition between near and far fields using a near-field particle tracking algorithm. It also employs the thermodynamic models to enable the prediction of oil properties under varying deep water pressure and temperature. To gauge the reliability and efficacy of DWOSM, a hypothetical case situated within a North American context is employed for model testing. The DWOSM and its each module are juxtaposed with other established oil spill models. The outcomes indicate that DWOSM yields comparable results to these models by providing reasonable predictions of a deepwater blowout. The model's verification through case scenario testing and comparison underscores its potential as a decision tool for assessing and managing the potential environmental impacts of offshore petroleum activities.

Onto Grid Purification and 3D Reconstruction of Protein Complexes Using Matrix-Landing Native Mass Spectrometry.

Addressing mixtures and heterogeneity in structural biology requires approaches that can differentiate and separate structures based on mass and conformation. Mass spectrometry (MS) provides tools for measuring and isolating gas-phase ions. The development of native MS including electrospray ionization allowed for manipulation and analysis of intact noncovalent biomolecules as ions in the gas phase, leading to detailed measurements of structural heterogeneity. Conversely, transmission electron microscopy (TEM) generates detailed images of biomolecular complexes that show an overall structure. Our matrix-landing approach uses native MS to probe and select biomolecular ions of interest for subsequent TEM imaging, thus unifying information on mass, stoichiometry, heterogeneity, etc., available via native MS with TEM images. Here, we prepare TEM grids of protein complexes purified via quadrupolar isolation and matrix-landing and generate 3D reconstructions of the isolated complexes. Our results show that these complexes maintain their structure through gas-phase isolation.